Theyre quite easy, you just ask a question then put it on the right branch of the tree. So as an example, "We asked 20 forum members what type of hamster they had. 15 had Syrians, 5 had dwarfs. Of the Syrian owners, 10 had bin cages, 3 had DIYs and 2 had Detolfs. Of the dwarf owners, 3 had detolfs and 2 had bin cages. Make this into a frequency tree"....
---------------------------- bin cage: 2
/ ------------------------ dwarf owner: 5 /
/ \ ------------------------------- detolf: 3
/
20 members------/
\
\ / -------------------------------- bin cage: 10
\ /
\---------------------Syrian owner: 15 ------------------------------- DIY: 3
\
\-------------------------------- detolf: 2
Thanks